The present invention relates to a resin sealing type semiconductor device, a manufacturing method thereof and a packaging structure thereof.
In recent years, with rapid advancements of IC cards and memory cards as well, a resin sealing type semiconductor device mounted in the card has been required to be made thinner. In response to this demand, a good number of methods of thinning the semiconductor device have been proposed.
One of those proposals is concerned with a structure in which the upper surface of a chip support and an undersurface of a semiconductor element are exposed as disclosed in, e.g., Japanese Patent Application No. 6273262-273262. According to this structure, a whole thickness of a package can be set on the order of 0.5 mm.
Further, as disclosed in Japanese Patent Laid-Open Publication No. 5-309983 (Japanese Patent Application No. 4-119133), a technique for reducing a packaging area is attained by bending a lead in an L-shape.
In the prior art resin sealing type semiconductor device described above, however, even when the package becomes thinner, the packaging area remains unchanged. That is, the lead extends long outside a mold resin, and hence an area of packaging on a printed circuit board is considerably wide as compared with the semiconductor element. This configuration is insufficient for actualizing high-density packaging.
The present invention aims at downsizing the resin sealing type semiconductor device and attaining the high-density packaging as well as at obviating the problems described above.
The present invention is:
(1) An upper layer of a surface formed with a semiconductor circuit is provided with an insulating layer composed of an insulating adhesive tape. A plurality of spot leads each electrically independent and regularly disposed are provided on the upper layer of the insulating layer. Further, a mold resinous portion is provided on side surface of at least of the insulating layer and the semiconductor element, thereby obtaining a resin mold package structure. Based on such a structure, it is feasible to downsize a resin sealing type semiconductor device and to attain high-density packaging-thereof.
(2) Moreover, in the structure of the item (1), a metal bump is formed in a portion provided with no insulating layer, i.e., with no insulating tape, whereby an electrical connection between the semiconductor element and the spot lead is actualized. Thus, the connection to the semiconductor element involves the use of not only the metal bump but also the insulating adhesive tape, thereby relieving stress upon the metal bump due to a difference in terms of thermal expansion. Then, it is possible to prevent an occurrence of deterioration and a decline in electric characteristic due to a fracture, etc. of the metal bump.
(3). In the structure of the item (1), an outside exposed surface of the spot lead is coated with metal plating. This metal plating may be coated on a surface opposite to the outside exposed surface, viz., on the surface on the side of the semiconductor element but should not be applied onto the side surface of the spot lead. More specifically, no metal plating is applied to a contact portion, with the mold resinous portion, provided on the side surface, thereby making it feasible to prevent a crack in the resin after molding.
(4). According to the structure of the item (1), a support portion composed of the same member as the spot lead but independent of the spot lead is provided on the upper layer of the insulating layer. The support portion may be provided so as to extend through a central portion of the semiconductor device surface on which the spot leads are arranged. The support portion is provided in this manner, and the structure of the semiconductor device can be strengthened, whereby a solid and highly reliable semiconductor device can be obtained.
(5). In the structure of the item (4), the spot lead and the support portion are provided in a state where these two components are so formed as to have continuity from each other through a lead frame, and are independently separated from each other by cutting the lead frame. Thus, the spot lead and the support portion can be formed simultaneously by use of the lead frame, and therefore a semiconductor device strengthened structurewise is obtained with a less number of steps.
(6). According to the structure of the item (2), the spot lead is provided with an extension lead and is electrically connected to the semiconductor element through the metal bump at a midway portion or a front edge of this extension lead. Thus, the spot lead serving as an external terminal is provided with the extension lead extending up to a junction area on the semiconductor element as a wire extends, and the metal bump is connected to this extension lead. Hence, the external terminals (spot leads) can be formed in array without depending much on positions of the junction areas for forming the circuit on the semiconductor element.
(7). According to a method of-manufacturing a resin sealing type semiconductor device, to begin with, (a) a support portion in a lead frame is fixedly adhered to a plurality of spot leads leastwise at one surfaces thereof by use of an insulating adhesive tape, and (b) the plurality of spot leads are separated from the lead frame. Thus, since the support portion and the spot leads are simultaneously formed, a manufacturing efficiency can be enhanced.
(8). According to a method of manufacturing a resin sealing type semiconductor device, (a) a support portion in a lead frame is fixedly adhered to a plurality of spot leads after metal plating at one surfaces thereof by use of an insulating adhesive tape, (b) the plurality of spot leads are separated from the lead frame, and (c) a semiconductor element is adhered to the other surface of the adhesive tape, and the semiconductor element is resin-sealed with a mold resin. In this way, the spot lead after the metal plating is fixedly adhered by use of the insulating adhesive tape and thereafter punched out (cut out). Therefore, the spot lead is fixed in a target position and in a predetermines size as well. Further, the metal plating is previously performed and therefore becomes unnecessary afterward even in the step of assembling the semiconductor device.
Moreover, the semiconductor element is stably supported by the adhesive tape, and further the solid resin sealing type semiconductor device can be obtained with the support portion.
(9). An insulating layer composed of an insulating adhesive tape is provided on an upper layer of a surface formed with the semiconductor circuit. Provided are a plurality of spot leads respectively electrically independent and regularly disposed on an upper layer of the insulating layer, and the structure is that front edges of the spot leads extend downward in an L-shape from outside the side portion of the-semiconductor element. Also, a mold resinous portion formed on side surfaces of at least the insulating layer and the semiconductor element, thus providing a resin mold package structure. In this way, the L-shaped leads are exposed to outside along the side surfaces of the semiconductor element, and it is therefore possible to enhance a junction strength of solder for connecting the external terminal to a foot pattern of the printed circuit board.
(10). According to a method of manufacturing a semiconductor device, (a) one surfaces of a plurality of spot leads in a lead frame are fixedly adhered by use of an insulating adhesive tape, (b) the semiconductor element is adhered to the other surface of the adhesive tape and is sealed with a resin, and (c) the plurality of spot leads are separated from the lead frame, and front edges of the spot leads are bent downward in an L-shape from outside the side portion of the semiconductor element. In this manner, the formation of the spot lead is not that mold resin sealing is performed after work-forming the lead frame but that the lead frame is work-formed after the mold resin sealing step in the assembly of the semiconductor device. It is therefore feasible to manufacture the resin sealing type semiconductor device capable of high-density packaging.
(11). According to a method of packaging a semiconductor device, (a) there are disposed, in a side-by-side relationship, a plurality of semiconductor devices including a plurality of L-shaped leads exposed to outside from upper surfaces of semiconductor elements within mold resinous portions, with their front edges extending downward from outside the side portions of the semiconductor elements, and the L-shaped leads are connected to each other. Then, (b) connecting portions of the L-shaped leads are connected to the same foot pattern provided on a wiring board. Accordingly, the two L-shaped leads can be connected together to the foot pattern on the same printed wiring board.
(12). According to a structure of an aggregate type semiconductor device, there are prepared a plurality of semiconductor devices including a plurality of L-shaped leads exposed to outside from upper surfaces of semiconductor elements within mold resinous portions, front edges of which extend downward from outside the side portions of the semiconductor elements. Then, the semiconductor devices are disposed in a face-to-face relationship so that front edges of the L-shaped leads face to each other, and the front edges of the L-shaped leads are connected to each other. That is, the upper resin sealing type semiconductor device is reversely laminated on the lower resin sealing type semiconductor device packaged on the board, and the front edges of the L-shaped leads of the respective resin sealing type semiconductor devices are connected. Thus, the upper resin sealing type semiconductor device is reversely laminated on the lower resin sealing type semiconductor device packaged on the board, and the front edges of the L-shaped leads of the individual resin sealing type semiconductor devices are connected. It is therefore possible to attain high-density packaging on the board.
(13). In the aggregate type semiconductor device in the item (12), resin packages are each composed of a mold resin in the plurality of semiconductor devices, and undersurfaces of the resin packages are fixed to each other with an adhesive agent. Thus, the undersurfaces of the upper and lower resin sealing type semiconductor devices are fixed to each other by use of the adhesive agent, and consequently the solid compact aggregate semiconductor device can be obtained.
(14). According to a structure of the aggregate type semiconductor device, there are prepared a plurality of semiconductor devices including a plurality of L-shaped leads exposed to outside from upper surfaces of semiconductor elements within mold resinous portions, front edges of which extend downward from outside the side portions of the semiconductor elements. Then, the plurality of semiconductor devices are laminated so that front edges of the L-shaped leads are set mutually in the same direction. That is, the upper semiconductor device is further laminated in the same direction on the lower semiconductor device. With further laminations in the same direction, the aggregate type semiconductor device having more multi-layers is to be obtained. For example, the semiconductor devices are superposed in three layers by laminating one more resin sealing type semiconductor device, and the L-shaped leads thereof are connected, thereby making it feasible to acquire much-higher-density packaging upon the board.
(15). According to the structure of the item (14), in the plurality of laminated semiconductor devices, the front edge of the L-shaped lead of the upper semiconductor device is connected to a bent portion of the L-shaped lead of the lower semiconductor device. In this way, the upper semiconductor device is laminated in the same direction on the lower semiconductor device packaged on the board, and the front edge and the bent portion of the L-shaped leads of the respective semiconductor devices, are connected to each other. Hence, the still-higher-density packaging on the board is attainable simply by laminating the resin sealing type semiconductor devices sequentially in the same direction.
(16). According to the structure of the item (14), resin packages are each composed of a mold resin in the plurality of semiconductor devices, and an undersurface of the resin package of the upper semiconductor device is fixed to an upper surface of the resin package of the lower semiconductor device by use of an adhesive agent. Thus, the upper and lower semiconductor devices are fixed to each other by using the adhesive agent, and the solid compact semiconductor device can be thereby obtained.